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suicideneil
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08.05.2009, 07:41 PM

Generally speaking, with the larger motors we aim for about 30-40,000rpms on the selected voltage, as this is the most efficient range. Same general rule applies to smaller motors, though they can spin faster as there is less rotating mass so the rotors are less likely to fly apart at high rpms. Running very high rpms all the time isnt all that good for the bearings mainly, even if they are rated for 60,000rpms- you end up having to gear down a whole ton to acheive usable speeds.

I would aim for a ~3000kv motor, that way it will be good on 2s and 3s lipo- 4s is probably overkill for such little vehicles, but then again its worth reading around.
   
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kazuaki
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08.05.2009, 07:49 PM

OK, so that points back to the 1.5Y, which is 3025kv. So, this motor is considerably different from the 4000kv VXL stock motor. I'm assuming I will run much taller gears with the Neu to make up for that difference, correct? It should have a lot more torque than my VXL?

Let me put it this way, the 1.5Y and the 2.5D should both push the truck to about the same terminal velocity if I gear each correctly, right? I just don't want to make the investment and find out I chose unwisely.
   
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kazuaki
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08.06.2009, 12:25 PM

Quote:
Originally Posted by kazuaki View Post
OK, so that points back to the 1.5Y, which is 3025kv. So, this motor is considerably different from the 4000kv VXL stock motor. I'm assuming I will run much taller gears with the Neu to make up for that difference, correct? It should have a lot more torque than my VXL?

Let me put it this way, the 1.5Y and the 2.5D should both push the truck to about the same terminal velocity if I gear each correctly, right? I just don't want to make the investment and find out I chose unwisely.
Can any of you more experienced guys confirm I am understanding this correctly? Does the KV rating really affect the power of the motor and the ultimate speed I will able to reach? Or does it merely affect the gearing I use to reach that ultimate speed?
   
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E-sav
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08.06.2009, 12:35 PM

It is better to have a lower KV, higher voltage setup as you will end up with a more efficient system. The problem is you are trying to cover an extremely large relative voltage range.

I would expect to maybe get a motor capable of running at 2s and 3s comfortably, but you are asking a lot to have it run safely at 4s too. I would say to get a motor that will be happy to run at 4s all the time, low kv, and just gear it for the speed you want. It makes more sense.

I run my slash 3s all the time. Just geared 19/86 for backyard bashing and geared 26/83 for on road speed kicks.
   
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zeropointbug
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08.06.2009, 12:49 PM

Quote:
Originally Posted by kazuaki View Post
Can any of you more experienced guys confirm I am understanding this correctly? Does the KV rating really affect the power of the motor and the ultimate speed I will able to reach? Or does it merely affect the gearing I use to reach that ultimate speed?
For a given motor, regardless of Kv., it's the RPM that determines the power output, for example:

1515/1Y(2200kv.) @ 4s lipo = 32560rpm

1515/2Y(1100kv.) @ 8s lipo = 32560rpm

Both will have virtually the same power output (the 2Y will have slightly more because of higher efficiency from the higher voltage), but nothing noticeable.


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kazuaki
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08.06.2009, 01:03 PM

So, sounds like the best option might be to get the 1110/1.5Y and run 4S for speed runs, but maybe run 3S (instead of 2S) for bashing. I guess I should optimize the power for the speed runs, where ultimate power is critical. Even the stock setup has more than enough power for bashing, so I guess I shouldn't worry about that so much.

Thanks for the help guys, I'll be ordering the 1110/1.5Y/3.2.
   
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kazuaki
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08.06.2009, 05:40 PM

Well, I saw the small price difference and made a last minute change to the 1112/2D. I couldn't help myself
   
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BL_RV0
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08.06.2009, 06:04 PM

MORE POWER!!!!!


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